[ExI] LIGO is back online

spike spike66 at att.net
Thu Dec 1 18:01:15 UTC 2016

-----Original Message-----
From: spike [mailto:spike66 at att.net] 

>...Chris cosmology is full of mind-blowing stuff, but consider for a giga
cubic parsec...if you had a giga-parsec^3 sphere out there about 300 million
light years, it could be total eclipsed by the moon.  Cool!

>...Since I did these numbers in my head, please check me on order of
magnitude at least, or sharpen it to a single digit of precision please,
astronomy hipsters.

>...If I did those numbers right, there are skerjillions of cubic
megaparsecs everywhere we gaze into the sky.  Moral of the story: space is
big.  Space is waaay big.  Spike

Eh, I think I missed that distance by a mere 3 orders of magnitude.  We
would only need to look about 300 thousand light years out past the moon to
gaze upon a sphere of volume giga cubic parsecs which could hide behind the
moon.  Had we looked out my original mental calculation of 300 million light
years, that moon-eclipsing sphere would be a billion giga cubic parsecs, or
perhaps we could call it an exa-cubic parsec sphere, or a giga giga cubic
parsec if we didn't mind risking getting the kids stirred up going around
giga giga-ing everything until ya want to swat em.

OK so that's why one should always do BOTECs with an actual B of the E.  I
missed the distance by 3 orders of magnitude and the volume by 9 orders, oy.

300 thousand LY isn't that far away, a tenth of the way to the nearest major
galaxy (not counting the dwarfs and local debris.)  The volume of the Milky
Way (depending on how you count it, such as a sphere out to here and ignore
everything outboard of us from the center of the galaxy) would be a couple
thousand cubic mega-parsecs.

Space is big.


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